Automatic valve for the removal of powdered material



Feb. 11, 1958 ,L. ROUJOB 2,8

AUTOMATIC VALVE FOR THE REMOVAL OF POWDERED MATERIAL Filed Dec. 2, 1955 LEO FOLD RO'UJOB BY if HTTOENEY n s-d ees AUTOMATIC VALVE FOR THE REMOVAL OF POWDERED MATERIAL Leopold Roujob, Brussels, Belgium, assignor to Societe Beige Prat Daniel, Brussels, Belgium, a corporation of Belgium Application December 2, 1955, Serial No. 550,700

3 Claims. (Cl. 214-17) My present invention relates to an automatic valve to evacuate powdered materials from a hopper or a tank under atmospheric, positive or negative pressure without escape of gas from one side of the valve to the other.

Automatic valves of my invention are particularly useful in evacuating the dust collected in dust separating apparatus, such as multi-tube centrifugal separators, but may also be used to discharge dust or fine particles collected in other apparatus.

In the flap valves heretofore used for the evacuation of dust, the flap is balanced by a counterweight and is operated by the weight of the material falling on the flap when the weight of this material overbalances the counterweight. This prior system has a number of disadvantages, particularly when it is connected to a hopper, the inside of which is under negative pressure. The first disadvantage is the influence of the friction of the material on the hopper walls and particularly the sloping walls which oppose the force of gravity which is applied to the flap and often brings about the so called bridging. The second disadvantage is the negative pressure which acts opposite to gravity. The result is that the effective weight of material acting on the flap is much less than the actual weight and the operation of the valve becomes unsatisfactory.

My present invention provides means to increase the effective weight of the material on the flap and, at the same time, to insure gas tightness between the two sides of the valve when there is a dilference of pressure.

In accordance with my invention, the operation of the valve is done by the weight of the material accumulated over the flap. However, instead of beingalso supported by the walls of the hopper, the material falls into a mobile vertical sleeve which may contain a large amount of material and from which it flows freely due to the fact that the wall of the sleeve does not converge downwardly but is preferably a vertical cylindrical wall and also that it is mobile and comes down with the material, thereby avoiding a good part of the friction.

The gas tightness between the flap and hopper is insured by a permanent seal of the material itself between the bottom part of the fixed sleeve which surrounds the mobile sleeve and the flap that presses on the edge of the fixed sleeve.

A counterweight or spring closes the flap and brings the mobile sleeve to its top position when the latter is nearly empty. When the weight of accumulated material is sufficient to overcome the counterweight, the inertia, the friction of the material on the fixed sleeve and the negative pressure in the hopper, the combined mobile sleeve and flap come down and the material flows out. The tilting of the lever arm of the mechanism and the inertia of the large amount of material that has accumulated allow a clear opening of the flap limited by an adjustable stop. There is a large amount of material that flows out and this prevents the flap from stopping in half-open position, as often happens with the prior systems of flap valve.

The-force of the counterweight is adjusted in such way that. the flap rises. when the mobile sleeve is' not; completely empty so that a certainamount of material remains in the fixed sleeve between the bottom part of the mobile sleeve and the flap. The height of this reserve of material is suificient to insure gas tightness. The output of material flowing out can be controlled by the position of the adjustable stop which limits the opening of the flap.

The invention is illustrated by way of example in the enclosed drawing which shows diagrammatically an embodiment of the invention.

In the embodiment of the invention shown in the attached drawing, the finely divided material accumulates in a hopper 1 which slopes downwardly to a cylindrical outlet 2. Secured to and depending from this outlet is a fixed outer sleeve 3 of larger diameter into which the outlet delivers. The finely divided material delivered through the outlet 2 falls into an axially movable vertical sleeve 4 open at each end. Preferably the lower end of the outlet is a short distance within the upper part of the sleeve 4.

The lower end of the fixed sleeve delivers into an evacuating chamber 5 having an inturned flange 6 secured to the end of the sleeve, this flange having a downwardly opening rim 7. Positioned within the chamber 5 is a horizontal flap or valve 8 suspended from the mobile sleeve 4 by means of a rod 9 and spider arms 10 and thus movable vertically with the sleeve 4 to an upper position against the lower edge of the rim 7 and a lower position spaced a distance from the lower edge of the rim.

The flap 8 is normally held tight against the rim 7 by a counterweight 9 suspended from one arm of a lever 10 pivoted on a bracket 11 on the outlet 2, the other arm of the lever being secured to the upper end of the rod 9. The lower end of the rod is guided in a cross beam 12 through which it is freely movable vertically.

The downward movement of the flap 8 is limited by an adjustable stop 13 on the rod 9 which, in the lowermost position of the flap, rests on the cross beam 12.

In operation, the powdered or finely divided material fills the lower part of the hopper and flows into the bottom part of the fixed sleeve 3 to form a seal against escape or entrance of gas in case there is a difference in pressure between the two sides of the flap. The powdered material rises to the bottom edge of the mobile sleeve 4 and fills it to a height corresponding to a weight equalling the force of the counterweight 9 connected to the flap 8 through the rod 9 and lever 10'. The flap then descends until the adjustable stop 13 rests on the cross beam 12, the mobile sleeve 4, to which it is attached by the rod 9 and arms 10, moving down with it and the mass of powdered material. The powdered material then flows out freelybecause of the pressure of material in the sleeve 4. When the mass of powdered material has decreased to such an extent that the force of the counterweight overbalances it the flap and mobile sleeve move upwardly until the flap seals against the edge of the rim 7.

Having described my invention, what I claim is:

1. A discharge valve for finely divided material which comprises, a vertically fixed, vertical outer'sleeve, a vertically movable sleeve within said outer sleeve, a valve seat at the lower end of said outer sleeve, a flap movable vertically to seat against said valve seat and operatively connected to, and moving with, said vertically movable sleeve, and a counterweight connected to said vertically movable sleeve and said flap to move said vertically movable sleeve and flap upwardly.

2. The apparatus of claim 1 having a rod connected to said flap and extending upwardly through said vertically movable sleeve, a lever connected to said rod and Patented Feb. 11,

to 'said counterweight, arms connecting said rod to said a stop adjustably mounted on said rod above said cross 5 beam to engage said cross beam and limit the downward movement of said flap.

References Cited in the file of this patent UNITED STATES PATENTS Wagner Sept. 17, 1889 Williams et a1 June 6, 1911 

